Wringer

ABSTRACT

A device for wringing fluid out of laminar articles by compressing the articles between two platens, one of which is covered on its article contacting face by an inflatable membrane and at least one of which is covered by a flexible web forming the article-contacting surface and made of porous material which has pores to permit water draining from the articles to be channelled to the side edges of the platen. The porous web allows efficient drainage of fluid and the inflatable membrane allows the exertion of a constant pressure over the article even when the article has an uneven surface, and is thus particularly suitable for the drying of treated leather.

United States Patent Busek Mar. 25, 1975 [541 WRINGER FOREIGN PATENTS ORAPPLICATIONS 1 Josef Busek, (iartenstrasse 16, 986,006 3/1963 UnitedKingdom 69/48 D-8190 Wolfratsha sen, rm ny 118.943 6/1958 U.S.S.R a.69/48 [22] Filed: Oct. 5, 1973 1 Primary E.\'aminerAlfretl R. Guest [21]Appl 404004 Attorney, Agent or Firm-Spencer & Kaye [30] ForeignApplication Priority Data [57] ABSTRACT O t. 9, 1972 G 2 Y 2249369 c ermm) A device for wrlngmg fluid out of lammar art1cles by 52 us. c1 69/4769/48 100/222 Compressing the articles between two platens" one of68/242 which is covered on its article contacting face by an [51] Int ClI Cl4b 17/00 inflatable membrane and at least one of which is cov- [58]Field 43; 68/242 ered by a flexible web forming the article-contacting68/21. ii 29/121 surface and made of porous material which has pores topermit water draining from the articles to be chan- [56] ReferencesCited nelled to the side edges of the platen.

UNITED STATES PATENTS The porous web allows efficient drainage of fluidand l 3 W970 the inflatable membrane allows the exertion of a 53 Q 3constant pressure over the article even when the 3/1911 article has anuneven surface, and is thus particularly 6/1953 suitable for the dryingof treated leather.

3.160.553 12/1964 3.181409 6/1965 GIZISS 29/121 R x 8 Clam, 2 DrawmgFlgules PATENTED MARZS I975 SHEET 2 or 2 WRINGER BACKGROUND OF THEINVENTION The invention relates to a device for wringing laminararticles, the device being particularly, though not exclusively, suitedto the wringing of articles of irregularly varying cross-sectionalthickness, such as leather.

Leather that has just been tanned is still extremely wet, and thismoisture needs to be removed. In the early days spindle presses wereemployed for this purpose, a plurality of leather skins being arrangedin superimposed layers between the platens, the platens depressed andthe press left for some considerable time while the liquid being wrungout trickled laterally out of the compressed material. However it wasnot possible with these presses to remove sufficient moisture.

The technology therefore changed to water extracting machines operatingessentially on the same principle as a laundry calender and having twoco-operating pressure rollers driven in opposite directions to squeezethe leather therebetween. In order to compensate for the irregularlyvaring cross-sectional thickness of leather being processed, each ofthese rollers may be covered with a layer of felt. It has been foundhowever that in use this felt covering is subject to considerable wearand tear since the rollers must not only fulfil the task of wringing butalso that of conveying the skins through the machine. More-over,operation of such machines requires considerable skill on the part ofthe operators in order to ensure that the leather skin is correctly fedinto the machine and to prevent the leather from creasing. Finally,because such machines must operate at a very high roller pressure, forexample of the order of some 70 atmospheres, in order to effect asatisfactory degree of wringing, the surface structure of the feltcovering becomes impressed in the surface of the leather, therebyrestricting the use to which the processed leather may be put.

SUMMARY OF THE INVENTION According to the present invention I provide adevice for wringing a laminar article comprising an article treatmentstation, first and second pressure members disposed within saidtreatment station and having respective article-contacting surfaces;means for effecting approach and separation of said pressure members;inflatable membrane carried by said first pressure member and facingsaid second pressure member; and a web of porous flexible materialinterposed between said membrane and said second pressure member to formone of the article-contacting surfaces, the pores of said porous webcommunicating between its edges and said one article-contacting surfaceto enable liquid to drain away from said one article-contacting surface.

The invention can thus provide an apparatus with a considerably higherthroughput than other noncalendering devices, without the quality of theend product or the efficiency of liquid extraction being impaired.

Tests carried out with a device according to the invention have shownthat a pressure of as little as to atmospheres suffices for the deviceto operate at the same level of effectiveness as conventional machines.It is, moreover, easier to prevent creasing when wringing, especially inthe border region of the skins being processed than with theconventional machines. Finally, the comparatively low wringing pressuremakes it possible to wring out doubled or folded skins, without thecrease remaining visible in the finished, wrung out skin. Finally, aplurality of superimposed leather skins can be wrung out with thisdevice.

Advantageously an intermediate layer is associated with each of thepressure surfaces. It has proved particularly advantageous to producethe intermediate layers of a fabric woven of monofilament fibers sincesuch woven fabrics are non-absorbent and enable without any difficultylateral drainage of the wrung out liquid.

The membrane may be pneumatically or hydraulically inflated. Water issuitably utilized as hydraulic inflation medium and has no detrimentaleffect on the leather when leakages occur in the membranous system.

For facilitating feeding the skin into the device and removal of theleather after completion of the wringing operation, at least one run ofat least one conveyor belt is guided between the pressure members. Thematerial of the conveyor belt should have substantially the sameproperties as the porous flexible webs so as not to hamper the lateraldischarge of the extracted liquid. Alternatively it would even bepossible to provide for the conveyor belt itself to serve as the porousflexible web.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a cross-section of oneembodiment of the device according to the invention; and

FIG. 2 shows a cross-section analogous to FIG. 1 of a slightly modifiedembodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to FIG. 1, theupper pressure surface is designated by the reference numeral 1, thelower one by the reference numeral .2. The lower pressure surface 2 isin the form ofa rubber membrane 4 spanning a support 3. The support 3 isstationary and forms part of the frame of the device. The gap betweenthe membrane 4 and the support 3 communicates via a supply line 5 with ahydraulic accumulator (not shown). The head of the device is designatedby the numeral 6, and is stationary like the support 3. In the head 6 apress ram 7 is longitudinally reciprocable in the direction of arrow 8along guideways schematically indicated at 9 and 10. The pressuresurface 1 is covered by a porous flexible web 11 and the pressuresurface 2 is covered by a similar web 12, both webs being laterallysecured in the region of securing rails 13 and 14, respectively. Thewebs 11, 12 are of a non-absorbent material, e.g. a synthetic 7material, and more suitably consist of a woven fabric of monofilamentfibers. The cross-sectional thickness of the webs must be so dimensionedthat an adequate draining towards the side is possible.

The upper web 11 is backed with a layer 15 of an absorbent material. Theabsorbent layer 15 is elastically compressible, and may thus be formedof a sponge or foam material.

The ram 7 is lockable in final adjusted position. To this end it isprovided with wedge-like sloping surfaces 16 on the reverse side. Twowedges 18 are adapted to be pushed into the gap between the slopingsurfaces 16 and the oppositely located face 17 when the ram 7 is in itsadjusted end position (not shown). The two wedges 18 are interconnectedby a rod 19 which is guided for longitudinal displacement in thedirection of the arrow 20 in the head 6.

Between the two webs l1, 12 passes the upper run 22 of a conveyor belt21. The lower run 23 of the conveyor 21 may be so routed that it alsopasses through the gap 24 between the two webs 11, 12. The conveyor belt21 is of a porous, flexible material having passages which enablelateral drainage of liquid. The material of the conveyor belt isnon-absorbent; the conveyor belt more particularly consists of asynthetic material, and in the exemplary embodiment it consists of amonofilament fiber fabric.

In the embodiment according to FIG. 2 the upper pressure surface 1 ofthe ram 7 is heatable by means of a heating coil 25.

The pressure surface 1 of the ram 7 of FIG. 1 is provided with spacedair ducts 26 communicating with a compressed air line 26a. In addition,these air ducts 26 may be connected with a suction line (not shown) forthe purposes of aiding liquid removal by suction during the processingstep. After the liquid removal operation air is blown through the sameair ducts 26 so as to be able to detach any leather 27 which may adhereto the web 11.

The device operates in the following manner. A leather skin 27 ispositioned, optionally in folded form, exteriorly of the device on theconveyor belt 21, e.g. in the region of an end roller 28. The skin isthen introduced into the gap 24 between the ram 7 and the support 3 bymoving the conveyor belt in the direction of arrow 29. While the skin 27is being fed into the gap 24, the ram 7 remains in its retractedposition (FIG. 1). Thereafter the ram 7 is moved toward the support 3.This is done by means of a hydraulic drive 30 in the head 6. Theadjustment is executed such that the ram 7 thrusts the skin 27 againstthe as yet untensioned membrane 4 and holds it there, optionally underslight compression. The ram 7 having been so positioned is thenpositively locked by shifting the rail 19 toward the left as seen inFIG. 1 (arrow direction 20). The wedges 18 are thereby positionedbetween the slopes 16 on the reverse side of the ram 7 and the head 6 ofthe device.

Hydraulic liquid is now pumped in the direction of arrow 31 through thehydraulic line into the gap between the membrane 4 and the support 3.The membrane is thereby slightly inflated. The full pressure of thehydraulic liquid urges the membrane against the skin 27. This pressuremay amount to about atmospheres for example. The flexibility of therubber membrane 4 ensures that a pressure of equal magnitude is exertedon all points of the skin 27, although the skin is not of the samecross-sectional thickness throughout. By virtue of the pressure exertedby the membrane 4 on the skin 27 the skin is compressed. The liquidcontained in the skin issues at both surfaces from the skin 27. Theliquid enters the transverse passages created by the porosity of theconveyor belt 21 and the webs l1, l2 and flows out from the sides ofupper run 22 of the conveyor belt 21 and the websll, 12. The peripheralregions from which the liquid issues are situated outside the contoursurfaces of the skin 27 so that the latter is not contacted by theliquid being squeezed out. It is clear that the cross-sectionalthickness and the structure of the webs ll, 12 and of the conveyor belt21 must be so arranged that lateral draining of the liquid issuing fromthe skin 27 during the wringing operation is ensured. This canadditionally be assisted, for example, by a reduced pressure beingproduced in the region of the air ducts 26 so that the issuing, liquidis in addition being sucked off. It is also possible to blow compressedair through the ducts 26 during the wringing operation, so as to assistthe lateral motion of the liquid squeezed from the webs ll, 12 and theconveyor belt 21.

After completion of the wringing operation the membrane 4 is deflated,the ram 7 is driven up, and compressed air is optionally blown throughthe ducts 26 to prevent the skin 27 from sticking to the web 11. Theconveyor belt is then moved on in the direction of arrow 29 so that thewrung-out skin can be removed from the belt at a station to the left, asviewed, for example, in FIG. 1.

While the webs 11, 12 have been described as nonabsorbent, it is to beunderstood that the device of the invention may readily be constructedwith webs which exert suction, for example by capillary forces.

We claim:

1. A device for wringing flat articles of irregular thickness, having astationary lower pressure member; a movable upper pressure memberoriented towards the stationary presssure member; means for moving themovable pressure member towards and away from the stationary pressuremember; an expansible membrane secured to the stationary pressure memberand having a face oriented towards the movable pressure member; meansfor expanding the membrane by liquid pressure for pressing the membraneface against the flat article situated between the two pressure members;a conveyor belt extending between the pressure members for positioningthe flat article therebetween, the conveyor belt being structured toallow liquid pressed from the article to flow parallel to the beltfaces; the improvement comprising: a first web affixed to saidstationary pressure member and extending over said membrane and saidstationary pressure member, said first web having a web face orientedtowards said conveyor belt; and a second web affixed to and extendingover said movable pressure member, said second web having a web faceoriented towards said conveyor belt; said first and second webs being ofa porous, essentially nonabsorbent structure for providing a drainage ofthe liquid, pressed from the flat article, within each said web in adirection parallel to said web faces.

2. A device as defined in claim 1, further comprising pneumatic meansconnected to said movable pressure member for forcing air through saidfirst web selectively in the one or the other direction.

3. A device as defined in claim 1, wherein said webs are made of asynthetic fiber.

4. A device as defined in claim 1, wherein said webs are made of a wovenfabric of monofilament fibers.

5. A device as defined in claim 1, further comprising a liquid-absorbentsponge layer disposed between said movable pressure member and saidfirst web.

6. A device as defined in claim 1, further comprising means for heatingat least that portion of said movable pressure member that is orientedtowards said second web.

7. A device as claimed in claim 1, wherein the conveyor belt isconstructed of a non-absorbent material.

8. A device as claimed in claim 1, wherein the conveyor belt isconstructed of a fabric of woven monofilamentary fibers.

1. A device for wringing flat articles of irregular thickness, having a stationary lower pressure member; a movable upper pressure member oriented towards the stationary presssure member; means for moving the movable pressure member towards and away from the stationary pressure member; an expansible membrane secured to the stationary pressure member and having a face oriented towards the movable pressure member; means for expanding the membrane by liquid pressure for pressing the membrane face against the flat article situated between the two pressure members; a conveyor belt extending between the pressure members for positioning the flat article therebetween, the conveyor belt being structured to allow liquid pressed from the article to flow parallel to the belt faces; the improvement comprising: a first web affixed to said stationary pressure member and extending over said membrane and said stationary pressure member, said first web having a web face oriented towards said conveyor belt; and a second web affixed to and extending over said movable pressure member, said second web having a web face oriented towards said conveyor belt; said first and second webs being of a porous, essentially non-absorbent structure for providing a drainage of the liquid, pressed from the flat article, within each said web in a direction parallel to said web faces.
 2. A device as defined in claim 1, further comprising pneumatic means connected to said movable pressure member for forcing air through said first web selectively in the one or the other direction.
 3. A device as defined in claim 1, wherein said webs are made of a synthetic fiber.
 4. A device as defined in claim 1, wherein said webs are made of a woven fabric of monofilament fibers.
 5. A device as defined in claim 1, further comprising a liquid-absorbent sponge layer disposed between said movable pressure member and said first web.
 6. A device as defined in claim 1, further comprising means for heating at least that portion of said movable pressure member that is oriented towards said second web.
 7. A device as claimed in claim 1, wherein the conveyor belt is constructed of a non-absorbent material.
 8. A device as claimed in claim 1, wherein the conveyor belt is constructed of a fabric of woven monofilamentary fibers. 